Field of the Invention
This invention relates to the field of a putty composition that can be used in the installation of drain pipes, sinks, faucets, and bath fixtures, and kitchen surfaces made of porous stone such as marble and granite, to create a water-tight seal and prevent leaks and seepage, and that will not permanently damage porous surfaces by not leaving behind a yellowish stain due its being formulated without any natural or hydrocarbon oils. More specifically, the present disclosure relates to a hydrophobic silicone-based non-staining putty composition.
Background
Plumber's putty is a well-known product in the plumbing and construction industry to seal fixtures in bath and kitchen areas, such as faucets, tub strainers, and sinks. This putty composition is well-known to be waterproof, adhesive, and easily manipulated by hand to be molded into any shape; it remains soft and flexible, and will not shrink or crack before or after being installed. Typical plumber's putty consists of inert fillers and a liquid portion that may contain hydrocarbon oils and natural oils. Traditionally fish oil was used for this application, Fish oil contains a variety of polyunsaturated acids, including docosenoic acid as the main component, and some others, usually of the C-22 carbon chain variety. In other embodiments, vegetable oils are used for this application, most commonly blown castor oil. The fatty acid chains present in castor oil include about 70% ricin oleic acid, a C-18 carbon chain acid. Due to the oils present in the typical composition of plumber's putty, the product makes a permanent yellowish stain around the installation area when applied on any kind of porous surfaces because of the migration of the oils out of the putty over the uncovered surface. This makes the product unsuitable for installations on marble, granite, or any other porous material.
There are a variety of techniques used by plumbers to prevent the staining caused by plumber's putty; some plumbers recommend the application of an acrylic coat to the surface on which the installation will take place, but this does not guarantee that the oil will not migrate over time to the untreated stone. Another alternative to protect the stone is to apply a stone sealer, but this is a very expensive product and requires a long time to dry and cure. Some stone sealers can also cause a discoloration that can result in a non-homogeneous color in the whole piece of the stone.
U.S. Pat. No. 7,434,812 (the '812 patent), incorporated by reference herein in its entirety, describes a putty that substitutes the use of vegetable and hydrocarbon oils with a silicone rubber, a polymeric plasticizer, and some clays, such as montmorillonite, kaolin clay, bentonites, and any other type of natural or synthetic clays. These clays have a high shrink-swell capacity, resulting in cracking which is a risk of the product to fail when it is not well-kneaded.
Viscosity or viscosity ranges of silicone compounds do not determine if they are classified as gums, rubbers, or fluids. Classification depends on the chemical structure of the polymeric chains. Silicone gum is a clear, high-molecular-weight polydimethyldiphenylvinyl-siloxane that can be compounded and vulcanized by normal silicone rubber procedures. Silicone rubbers are inorganic synthetic elastomers made from a cross-linked silicone-based polymer. Silicone rubber is a polymeric material with the consistency of gum. More specifically, silicone rubbers are inorganic synthetic elastomers of high molecular weight, typically polydimethyldiphenylvinyl-siloxane, which can be compounded and vulcanized by normal silicone rubber procedures. This material can be difficult to manufacture due to its rubbery properties, and its inclusion in the putty composition increases the risk of the product failing. In addition, this composition is an expensive alternative in comparison with the oil-based putty, making its use more suitable for luxury applications, porous stone applications, or where staining could be permanent.
U.S. Pat. No. 8,986,438 (the '438 patent), incorporated by reference herein in its entirely, describes another attempt to make an affordable product and to reduce the risk of staining a porous surface by replacing the rubbery component with vegetable oil and adding zeolites to absorb the oil, preventing its migration to the stone's surface. But is has been found that this composition does not guarantee that the product will not cause permanent damage to the marble or to any other natural porous stone, because staining can occur as long as there is any, or combination of, natural, synthetic, and hydrocarbon oils.